The send_xchar() and tiocmset() tty operations are optional. Add the
missing sanity checks to prevent user-space triggerable NULL-pointer
dereferences.
Fixes: 6b9ad1c742bf ("staging: speakup: add send_xchar, tiocmset and input functionality for tty")
Cc: stable <stable@xxxxxxxxxxxxxxx> # 4.13
Cc: Okash Khawaja <okash.khawaja@xxxxxxxxx>
Cc: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
drivers/staging/speakup/spk_ttyio.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/speakup/spk_ttyio.c b/drivers/staging/speakup/spk_ttyio.c
index c92bbd05516e..005de0024dd4 100644
--- a/drivers/staging/speakup/spk_ttyio.c
+++ b/drivers/staging/speakup/spk_ttyio.c
@@ -265,7 +265,8 @@ static void spk_ttyio_send_xchar(char ch)
return;
}
- speakup_tty->ops->send_xchar(speakup_tty, ch);
+ if (speakup_tty->ops->send_xchar)
+ speakup_tty->ops->send_xchar(speakup_tty, ch);
mutex_unlock(&speakup_tty_mutex);
}
@@ -277,7 +278,8 @@ static void spk_ttyio_tiocmset(unsigned int set, unsigned int clear)
return;
}
- speakup_tty->ops->tiocmset(speakup_tty, set, clear);
+ if (speakup_tty->ops->tiocmset)
+ speakup_tty->ops->tiocmset(speakup_tty, set, clear);
mutex_unlock(&speakup_tty_mutex);
}
--
2.20.1
